It's said that people trapped in comas and vegetative states envision themselves in another world. A world in which they are free to roam, reshape their life, and have a second chance at existence. When they don't wake up, it's said to be because they believe in their envisioned world so much, they've entirely forgotten that they belonged anywhere else. It's also said that, sometimes, they are given a window. A window through which they can view the world they left behind. A window that can take the shape of a movie, a television show, or even a book.
3 parts